Anterior Cruciate Ligament Injury (ACL)

Anterior cruciate ligament is one of the paired crossed ligaments inside the knee. It connects the thighbone to shinbone and provides stability against anterior translation of the knee.

Anterior cruciate ligament is commonly injured during high demand sports, like soccer, tennis, volleyball and basketball etc. It can be sprained or torn during the game. The severity of its injury is graded into 3 levels:

Grade I: Ligament is sprained and its structural integrity is preserved.
Grade II: Ligament is partially torn.
Grade III: Ligament is completely torn.

Other intra-articular knee structures, e.g. meniscus, articular cartilage and lateral collateral ligament may be injured at the same time.

Causes of anterior cruciate ligament

The anterior cruciate ligament is usually injured indirectly during cutting, turning and jumping. The injury takes place without direct body contact. If your ACL is torn during the game, you may have heard a “pop” sound and then sudden knee pain that makes you inability to continue the game.

Players of high demand sports (e.g. soccer, basketball, skiing, etc.) will be at risk. Women participants of these sports will be more risky than men.

Symptoms of anterior cruciate injury

If you got ACL injury, you may experience:

knee pain
progressive knee swelling
limited knee movement
knee locking
sense of instability, givingway

Diagnosis of anterior cruciate ligament injury

Anterior cruciate ligament is diagnosed via history, physical examination and imaging. The doctor may examine both of your knees. X-Ray and Magnetic resonance imaging (MRI) are the two common radiological investigations for confirmation of the diagnosis.

X-Ray:
X-Ray is useful to look for other concomitant bony injury around the knee.
MRI:
MRI has surpassed other imaging studies for diagnosis of ACL injury. It has high sensitivities and specificities for picking up ACL tear.

Treatment of anterior cruciate ligament injury

The doctor will help you to control knee pain and swelling at acute phase of the injury. These can be done by:

Rest: immobilization with brace or splint will help to ease the pain in first few day after the injury.
Ice therapy: cools the injured knee to control pain and swelling.
Compression: using bandage, stockinet or soft knee brace can help controlling swelling.
Elevation: to control leg swelling.
Physiotherapy: physiotherapist will design treatment modalities to relieve your symptoms.
Medications: analgesics will be prescribed by the doctor to ease your pain.

There are 2 subsequent management strategies for ACL injury: conservative and operative management.

Conservative management:
Non-operative management will aim at regaining full knee range and muscular strength. The doctor will collaborate with physiotherapist to design an optimal rehabilitation program for you.

Operative management:
The doctor will use autologous tendon or ligament graft to reconstruct your severed anterior cruciate ligament. The common grafts are hamstring tendon and patellar bone-tendon-bone graft.

Rehabilitation management:
Rehabilitation usually takes months to complete. These include knee range of motion exercise, muscular strengthening exercise and agility training.

Last Updated : Aug 2017

Please note that all medical health articles featured on our website have been reviewed by Quality Healthcare doctors. The articles are for general information only and are not medical opinions nor should the contents be used to replace the need for personal consultation with a qualified health professional on the reader’s medical condition.